An RAF engineer has died after a Red Arrows jet crashed in a "big fireball" at the air force's fighter pilot training ground at RAF Valley, north Wales.
The pilot of the aircraft survived the incident and is currently receiving medical care.
Witnesses reported seeing someone eject from the aircraft with a parachute before it smashed into the ground then "burned bright orange".
Captain Nick Tucker-Lowe confirmed the death at a press conference outside the airbase.
He said: "The engineer's family have been informed and have asked for a 24-hour period of grace before further details are released."
A spokesman for the Welsh Ambulance Service confirmed an emergency ambulance and a Wales Air Ambulance attended the scene.
Anne Wilson, who works at The Anglesey Golf Club close to the airbase, witnessed the aftermath of the crash.
She said: "I did go and have a look and there was a big fireball and lots of dark smoke ... quite a few of the members actually saw it.
"They said the plane came in quite steeply and saw a pilot eject, but that it was very low to the ground when they ejected."
The Red Arrows Twitter account posted: "We are aware of an incident today at RAF Valley involving a Hawk aircraft. We are investigating the incident."
It is understood the Red Arrows aircrew had been at RAF Valley for routine Hawk simulator training - something that takes place once a month.
They had just taken off from the base and were on their way back to RAF Scampton, where the aerobatic team are based, when the incident happened.
Based at RAF Scampton in Lincolnshire, all Red Arrows pilots have flown operationally in frontline aircraft before joining the display team.
The RAF has asked anyone who saw the incident to send photographs to firstname.lastname@example.org in order to help with the investigation.